The Indiana Speech Training Aid (ISTRA). I: Comparisons between human and computer-based evaluation of speech quality.

Experimental comparisons are reported between computer-based and human judgments of speech quality for the same sets of utterances. Speech stimuli were recorded from two normal talkers, who intentionally varied the quality of their speech, and from a hearing-impaired child who was receiving speech therapy on the Indiana Speech Training Aid (ISTRA). The tape recordings were submitted for evaluation to a naive jury, an expert jury, and the ISTRA System, a microcomputer equipped with a speaker-dependent speech recognition board that generated scores representing how well utterance matched a stored template. Correlational analyses of these data indicated that humans were slightly better at judging speech quality than was the computer, but that the computer was much more reliable. These results demonstrate that computer-based speech evaluation may be a reasonable substitute for human judgments for certain types of speech drill.